The present invention relates to safety ski bindings, and more specifically to ski bindings of the type having a sole-plate to which the sole of a ski boot is releasably secured. At least one end of the sole-plate is secured to the ski surface by a flexible cable which is placed under continuous tension thus urging the sole-plate toward the ski. Ski bindings of this type are often referred to as retractable bindings in that the sole-plate, after release, has a return capability to the skiing position. Typical is the binding described in U.S. Pat. No. 3,893,682.
In another binding of this general type, described in U.S. Pat. No. 3,924,866, each end of the sole-plate is connected to the ski by a cable. Each cable has one end connected to the ski and the other end to a system of levers or winders within a housing the function of which is to provide the holding tension between the boot and ski and to vary the holding effort of the binding during release. The elongation allowed each cable by this system during release is not great. Accordingly the amount of displacement between the boot and ski is also not great which can lead to injury.
The safety ski binding according to the invention remedies the above-mentioned disadvantage by permitting, on release, a relatively considerable elongation of the cable, which, for example, can be equal to three or four times the elongation that would be permitted by a spring return device alone. This permits the sole-plate and ski boot to separate from the ski a sufficient distance to minimize the possibility of injury causing contact. At the same time, a predetermined ratio is maintained between the release effort and the tension of the spring return device.
Moreover, the present invention comprises a further improvement over known bindings by attaining the aforementioned cable elongation utilizing only one cable tensioning or return mechanism. This reduces the possibility of mechanical failure in such bindings and also achieves a desirable reduction in weight.